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The worms colonize the methane ice and appear to survive by gleaning bacteria, which in turn metabolize the clathrate. In 1997, Charles Fisher, professor of biology at Pennsylvania State University, discovered the worm living on mounds of methane ice at a depth of half a mile (~800 m) on the ocean floor in the Gulf of Mexico. [2]
The ice-core methane clathrate record is a primary source of data for global warming research, along with oxygen and carbon dioxide. Methane clathrates used to be considered as a potential source of abrupt climate change, following the clathrate gun hypothesis. In this scenario, heating causes catastrophic melting and breakdown of primarily ...
Carbon dioxide and methane are examples of greenhouse gases. The additional greenhouse effect leads to ocean warming because the ocean takes up most of the additional heat in the climate system. [3] The ocean also absorbs some of the extra carbon dioxide that is in the atmosphere. This causes the pH value of the seawater to drop. [4]
Methane's GWP 20 of 85 means that a ton of CH 4 emitted into the atmosphere creates approximately 85 times the atmospheric warming as a ton of CO 2 over a period of 20 years. [23] On a 100-year timescale, methane's GWP 100 is in the range of 28–34. Methane emissions are important as reducing them can buy time to tackle carbon emissions. [24] [25]
Ocean circulation events cause this process to be variable. For example, during El Nino events there is less deep ocean upwelling, leading to lower outgassing of carbon dioxide into the atmosphere. [18] Biological processes also lead to ocean-atmosphere carbon exchange. Carbon dioxide equilibrates between the atmosphere and the ocean's surface ...
Human activities affect marine life and marine habitats through overfishing, habitat loss, the introduction of invasive species, ocean pollution, ocean acidification and ocean warming. These impact marine ecosystems and food webs and may result in consequences as yet unrecognised for the biodiversity and continuation of marine life forms. [3]
Examples of tipping points include thawing permafrost, which will release methane, a powerful greenhouse gas, or melting ice sheets and glaciers reducing Earth's albedo, which would warm the planet faster. Thawing permafrost is a threat multiplier because it holds roughly twice as much carbon as the amount currently circulating in the atmosphere.
In the Arctic, the main human-influenced sources of methane are thawing permafrost, Arctic sea ice melting, clathrate breakdown and Greenland ice sheet melting. This methane release results in a positive climate change feedback (meaning one that amplifies warming), as methane is a powerful greenhouse gas. [ 3 ]